x/sys: some trampolines on darwin/amd64 still causing "unexpected return pc for runtime.sigpanic"

[mark-rushakoff]

What version of Go are you using (go version)?

$ go version
go version devel go1.17-e3769299cd Tue May 4 00:56:00 2021 +0000 darwin/amd64

Does this issue reproduce with the latest release?

n/a

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/mr/Library/Caches/go-build"
GOENV="/Users/mr/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOINSECURE=""
GOMODCACHE="/Users/mr/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/mr/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/Users/mr/gotip/src/github.com/golang/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/Users/mr/gotip/src/github.com/golang/go/pkg/tool/darwin_amd64"
GOVCS=""
GOVERSION="devel go1.17-e3769299cd Tue May 4 00:56:00 2021 +0000"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/tmp/goissue45702/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -arch x86_64 -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/ct/bl4_z3g51ks8239_r2k07v_40000gn/T/go-build4031339727=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

I regularly build and test our closed source projects with go tip. They had been running and testing fine until recently, when I started seeing some unexpected return pc panics.

I commented at #45702 (comment), but in hindsight that may have been a slightly different, although related, issue.

@cherrymui's fix in 731a015 stopped my minimized reproducer from crashing, but then when I rebuilt the primary project with go tip including that fix, I saw two new trampoline calls in the stack from different tests.

It looks like the existing use of funcPC at e.g. https://github.com/golang/sys/blob/0981d6026fa6241c75c6949829b5bd7a2574ad55/unix/zsyscall_darwin_amd64.go#L690 ought to also switch to internal/abi.FuncPCABI0 (maybe?), but I am not sure whether x/sys is allowed to call into internal/abi. Nor am I sure whether that is the appropriate fix.

What did you expect to see?

Tests passing.

What did you see instead?

Two new panics related to golang.org/x/sys/unix.libc_munmap_trampoline+0x0000000000000005 and golang.org/x/sys/unix.libc_ioctl_trampoline+0x0000000000000005. I assume this needs to be fixed beyond just those two cases, but those are the first two I've hit in our codebase.

One runtime stack for ioctl

fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb01dfacedebac1e pc=0x7fff708253a6]

runtime stack:
runtime: unexpected return pc for runtime.sigpanic called from 0x7fff708253a6
stack: frame={sp:0x7ffeefbff3a8, fp:0x7ffeefbff3f8} stack=[0x7ffeefb80448,0x7ffeefbff4b0)
0x00007ffeefbff2a8:  0x01007ffeefbff2c8  0x0000000000000004
0x00007ffeefbff2b8:  0x000000000000001f  0x00007fff708253a6
0x00007ffeefbff2c8:  0x0b01dfacedebac1e  0x0000000000000001
0x00007ffeefbff2d8:  0x00007ffeefbff378  0x0000000004037ff1 <runtime.throw+0x0000000000000071>
0x00007ffeefbff2e8:  0x000000000505278e  0x00007ffeefbff330
0x00007ffeefbff2f8:  0x00000000040382a8 <runtime.fatalthrow.func1+0x0000000000000048>  0x000000000592eba0
0x00007ffeefbff308:  0x0000000000000001  0x0000000000000001
0x00007ffeefbff318:  0x00007ffeefbff378  0x0000000004037ff1 <runtime.throw+0x0000000000000071>
0x00007ffeefbff328:  0x000000000592eba0  0x00007ffeefbff368
0x00007ffeefbff338:  0x0000000004038230 <runtime.fatalthrow+0x0000000000000050>  0x00007ffeefbff348
0x00007ffeefbff348:  0x0000000004038260 <runtime.fatalthrow.func1+0x0000000000000000>  0x000000000592eba0
0x00007ffeefbff358:  0x0000000004037ff1 <runtime.throw+0x0000000000000071>  0x00007ffeefbff378
0x00007ffeefbff368:  0x00007ffeefbff398  0x0000000004037ff1 <runtime.throw+0x0000000000000071>
0x00007ffeefbff378:  0x00007ffeefbff380  0x0000000004038020 <runtime.throw.func1+0x0000000000000000>
0x00007ffeefbff388:  0x000000000505fae1  0x000000000000002a
0x00007ffeefbff398:  0x00007ffeefbff3e8  0x000000000404fbb6 <runtime.sigpanic+0x0000000000000396>
0x00007ffeefbff3a8: <0x000000000505fae1  0x00000000055d86c8
0x00007ffeefbff3b8:  0x00000000058c0680  0x000000000415c228 <testing.(*T).Run·dwrap·21+0x0000000000000048>
0x00007ffeefbff3c8:  0x0000000008c010e0  0x0000000000000008
0x00007ffeefbff3d8:  0x000000000bc02258  0x0000000000000000
0x00007ffeefbff3e8:  0x00007ffeefbff430 !0x00007fff708253a6
0x00007ffeefbff3f8: >0x00007ffeefbff430  0x0000000005877000
0x00007ffeefbff408:  0x000000000000084d  0x0000000004950f65 <golang.org/x/sys/unix.libc_ioctl_trampoline+0x0000000000000005>
0x00007ffeefbff418:  0x000000000406fb3f <runtime.syscall+0x000000000000001f>  0x000000c0000766a0
0x00007ffeefbff428:  0x000000000406f4ac <runtime.nanotime_trampoline+0x000000000000000c>  0x000000c000076670
0x00007ffeefbff438:  0x000000000406d2b0 <runtime.asmcgocall+0x0000000000000070>  0x0000000008880008
0x00007ffeefbff448:  0x0000000004bc27e6  0x0000000004bc2760
0x00007ffeefbff458:  0x0000000000021928  0x0000000000021928
0x00007ffeefbff468:  0x00000000000009b8  0x000000c0001fda00
0x00007ffeefbff478:  0x000000000406ed9a <racecall+0x000000000000001a>  0x0000000000000004
0x00007ffeefbff488:  0x00000000051b6f50  0x000000000592eba0
0x00007ffeefbff498:  0x00007ffeefbff4e0  0x000000000406b2c5 <runtime.mstart+0x0000000000000005>
0x00007ffeefbff4a8:  0x000000000406b27d <runtime.rt0_go+0x000000000000013d>
runtime.throw({0x505fae1, 0x55d86c8})

One runtime stack for munmap

fatal error: unexpected signal during runtime execution
[signal SIGSEGV: segmentation violation code=0x1 addr=0xb01dfacedebac1e pc=0x7fff708253a6]

runtime stack:
runtime: unexpected return pc for runtime.sigpanic called from 0x7fff708253a6
stack: frame={sp:0x70000cf92db8, fp:0x70000cf92e08} stack=[0x70000cf13298,0x70000cf92e98)
0x000070000cf92cb8:  0x010070000cf92cd8  0x0000000000000004
0x000070000cf92cc8:  0x000000000000001f  0x00007fff708253a6
0x000070000cf92cd8:  0x0b01dfacedebac1e  0x0000000000000001
0x000070000cf92ce8:  0x000070000cf92d88  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92cf8:  0x000000000556b839  0x000070000cf92d40
0x000070000cf92d08:  0x00000000040386e8 <runtime.fatalthrow.func1+0x0000000000000048>  0x000000c0006824e0
0x000070000cf92d18:  0x0000000000000001  0x0000000000000001
0x000070000cf92d28:  0x000070000cf92d88  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92d38:  0x000000c0006824e0  0x000070000cf92d78
0x000070000cf92d48:  0x0000000004038670 <runtime.fatalthrow+0x0000000000000050>  0x000070000cf92d58
0x000070000cf92d58:  0x00000000040386a0 <runtime.fatalthrow.func1+0x0000000000000000>  0x000000c0006824e0
0x000070000cf92d68:  0x0000000004038431 <runtime.throw+0x0000000000000071>  0x000070000cf92d88
0x000070000cf92d78:  0x000070000cf92da8  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92d88:  0x000070000cf92d90  0x0000000004038460 <runtime.throw.func1+0x0000000000000000>
0x000070000cf92d98:  0x000000000557c0fd  0x000000000000002a
0x000070000cf92da8:  0x000070000cf92df8  0x0000000004050196 <runtime.sigpanic+0x0000000000000396>
0x000070000cf92db8: <0x000000000557c0fd  0x000000000c679bd8
0x000070000cf92dc8:  0x0000000005031fe9  0x0000000000000000
0x000070000cf92dd8:  0x000000000c46f860  0x000000000c46f860
0x000070000cf92de8:  0x000003ff00000002  0x000003ffffffffff
0x000070000cf92df8:  0x000070000cf92e40 !0x00007fff708253a6
0x000070000cf92e08: >0x000070000cf92e40  0x00000000064ab000
0x000070000cf92e18:  0x0000000000000a4b  0x0000000004c442a5 <golang.org/x/sys/unix.libc_munmap_trampoline+0x0000000000000005>
0x000070000cf92e28:  0x000000000407009f <runtime.syscall+0x000000000000001f>  0x000000c0000fb498
0x000070000cf92e38:  0x000000c00032a000  0x000000c0000fb468
0x000070000cf92e48:  0x000000000406d7d0 <runtime.asmcgocall+0x0000000000000070>  0x0000000005027e20
0x000070000cf92e58:  0x000000000c6d9000  0x000000000502ca80
0x000070000cf92e68:  0x00000000055ed140  0x00000000055ed140
0x000070000cf92e78:  0x0000000000000bc0  0x000000c0001fd860
0x000070000cf92e88:  0x000000000406f2da <racecall+0x000000000000001a>  0x000070000cf92ef0
runtime.throw({0x557c0fd, 0xc679bd8})
	/Users/mr/gotip/src/github.com/golang/go/src/runtime/panic.go:1198 +0x71
runtime: unexpected return pc for runtime.sigpanic called from 0x7fff708253a6
stack: frame={sp:0x70000cf92db8, fp:0x70000cf92e08} stack=[0x70000cf13298,0x70000cf92e98)
0x000070000cf92cb8:  0x010070000cf92cd8  0x0000000000000004
0x000070000cf92cc8:  0x000000000000001f  0x00007fff708253a6
0x000070000cf92cd8:  0x0b01dfacedebac1e  0x0000000000000001
0x000070000cf92ce8:  0x000070000cf92d88  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92cf8:  0x000000000556b839  0x000070000cf92d40
0x000070000cf92d08:  0x00000000040386e8 <runtime.fatalthrow.func1+0x0000000000000048>  0x000000c0006824e0
0x000070000cf92d18:  0x0000000000000001  0x0000000000000001
0x000070000cf92d28:  0x000070000cf92d88  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92d38:  0x000000c0006824e0  0x000070000cf92d78
0x000070000cf92d48:  0x0000000004038670 <runtime.fatalthrow+0x0000000000000050>  0x000070000cf92d58
0x000070000cf92d58:  0x00000000040386a0 <runtime.fatalthrow.func1+0x0000000000000000>  0x000000c0006824e0
0x000070000cf92d68:  0x0000000004038431 <runtime.throw+0x0000000000000071>  0x000070000cf92d88
0x000070000cf92d78:  0x000070000cf92da8  0x0000000004038431 <runtime.throw+0x0000000000000071>
0x000070000cf92d88:  0x000070000cf92d90  0x0000000004038460 <runtime.throw.func1+0x0000000000000000>
0x000070000cf92d98:  0x000000000557c0fd  0x000000000000002a
0x000070000cf92da8:  0x000070000cf92df8  0x0000000004050196 <runtime.sigpanic+0x0000000000000396>
0x000070000cf92db8: <0x000000000557c0fd  0x000000000c679bd8
0x000070000cf92dc8:  0x0000000005031fe9  0x0000000000000000
0x000070000cf92dd8:  0x000000000c46f860  0x000000000c46f860
0x000070000cf92de8:  0x000003ff00000002  0x000003ffffffffff
0x000070000cf92df8:  0x000070000cf92e40 !0x00007fff708253a6
0x000070000cf92e08: >0x000070000cf92e40  0x00000000064ab000
0x000070000cf92e18:  0x0000000000000a4b  0x0000000004c442a5 <golang.org/x/sys/unix.libc_munmap_trampoline+0x0000000000000005>
0x000070000cf92e28:  0x000000000407009f <runtime.syscall+0x000000000000001f>  0x000000c0000fb498
0x000070000cf92e38:  0x000000c00032a000  0x000000c0000fb468
0x000070000cf92e48:  0x000000000406d7d0 <runtime.asmcgocall+0x0000000000000070>  0x0000000005027e20
0x000070000cf92e58:  0x000000000c6d9000  0x000000000502ca80
0x000070000cf92e68:  0x00000000055ed140  0x00000000055ed140
0x000070000cf92e78:  0x0000000000000bc0  0x000000c0001fd860
0x000070000cf92e88:  0x000000000406f2da <racecall+0x000000000000001a>  0x000070000cf92ef0
runtime.sigpanic()
	/Users/mr/gotip/src/github.com/golang/go/src/runtime/signal_unix.go:719 +0x396

[cherrymui]

Thanks for reporting. I think we can continue on the previous issue, which is still open. Closing this as a dup. Thanks.